Electrical switching device and method for making



M r h 22, 9 B. DAL BIANCO ETAL 25,933

ELECTRICAL SWITCHING DEVICE AND METHOD FOR MAKING 2 Sheets-Sheet 1Original Filed March 18, 1958 FIGI.

l'n en 0r 33.3112

ian o- By M. Scata.

A ttorney March 22, 1966 B, DAL BIANCO ETAL Re. 25,988

ELECTRICAL SWITCHING DEVICE AND METHOD FOR MAKING Original Filed March18, 1958 2 Sheets-Sheet 2 Inventor 35.1212 Blancata BY 01M ttdrneyUnited States Patent Ofiice Re. 25,988 Reissued Mar. 22, 1966 25,988ELECTRICAL SWITCHING DEVICE AND METHOD FOR MAKING Bruno Dal Bianco,Milan, and Mario Scata, Monza, Italy,

assignors to International Standard Electric Corporation, New York,N.Y., a corporation of Delaware Original No. 3,059,074, dated Oct. 16,1962, Ser. No. 722,194, Mar. 18, 1958. Application for reissue Oct. 14,1964, Ser. No. 418,364 Claims priority, application Italy, Apr. 9, 1957,570,614 11 Claims. (Cl. 200-87) Matter enclosed in heavy brackets II]appears in the original patent but forms no part of this reissuespecification; matter printed in italics indicates the additions made byreissue.

This invention relates to switching devices and particularly to a devicefor the control of electrical circuits.

An object of this invention is to provide a switching device which iseasy to manufacture, economical, reliable and which can be replacedwithout difficulty. It is also designed to be fabricated in massproduction by automatic machines.

Heretofore there have been used devices for the control of electricalcircuits which comprise a vessel, air evacuated or filled with an inertgas, containing a movable magnetic structure operated by externalmagnetic forces to control the circuit making and breaking contacts ofsuch devices. Said movable armatures are generally made with magneticmaterial wires sealed into the ends of a glass tube and having a portionof the free ends thereof, enclosed inside the tube, overlapped in orderto be approached and to make contact by means of an external magneticforce.

Such relays in addition to having various drawbacks such as complexmounting inside the protective vessel, require the delicate adjustmentand are difficult to manufacture.

One of the features of this invention is to provide an electric circuitcontrolling device made with magnetic material, of small size, sealed atone end only of a container vessel, having one movable part only and astationary part, both extending inside said tube from said single end,the electric contacts and the magnetic material of the supports beingprotected from corrosion and oxidation as the vessel is air evacuated orfilled with an inert gas, said last operations being made from the endopposite to that into which said metal parts are sealed, facilitatingmass production of such devices.

Another feature of this invention is to form the whole magneticstructure starting from a single bar of magnetic material after havingsubjected it to a few mechanical operations to shape it in accordancewith the required application.

A further feature of this invention is to provide a metallic, rigid andcomplete structure in a single piece, after having been shaped, to beinserted into the container vesel from one end thereof and there sealedwithout the help of special tools, to support the members Within thetube, the external terminals of the switching device being placed at oneend of the container vessel offering a number of advantages in itsmanufacture, in its supporting arrangement and in its application.

Another feature of the present invention is to form the whole magneticmember from a single rod or wire made of magnetic material subjectingsaid rod or wire to a limited number of mechanical operations to shapeit according to the required employment.

A further feature of this invention is to shape in a particular way aportion of the magnetic structure, the movable one, whereby there isexploited the alternative actions of attractions and repulsions built upin the movable element, carrying the contact, under the action of theelectromagnetic external field, resulting in a firm contact closureusing a magnetic field of low intensity and providing a damping actionon the rebound effect of the movable member, with consequent advantages.

A further feature of the present invention is to obtain a single rigidand complete unit with a single piece, to be then introduced into thecontainer tube and there sealed without special tools to adjust metallicelements inside the tube, the switch device being mechanically andelectrically adjusted before being introduced in the protective vessel;external terminals of the switch device being perfected after sealing ofthe switch member inside the container tube, providing therefore severaladvantages and making its manufacture easy.

The above-mentioned and other features and objects of this inventionwill become apparent by reference to the following description taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a side view of a rod or wire of magnetic material before beingfabricated into contact springs in accordance with the invention;

FIG. 2 is a longitudinal plan View of the rod shown in FIG. 1 after ithas been subjected to a number of forming operations;

FIG. 3 is a front view of the rod shown in FIG. 2;

FIG. 4 is a front view of the rod shown in FIG. 3 after it has beensubjected to a number of further forming operations;

FIG. 5 is a front view partly in section of the structure of FIG. 4placed within an envelope;

FIG. 6 is a longitudinal plan view of the rod shown in FIG. 1 after ithas been subjected to a number of forming operations according toanother embodiment of the invention;

FIG. 7 is a front view of the rod shown in FIG .6 after it has beensubjected to a number of further forming operations;

FIG. 8 is a front view partly in section of the structure of FIG. 7placed within an envelope; and

FIG. 9 is a front view of the entire structure of FIG. 8 and the mannerin which the connecting terminals are formed and the energizing coil isplaced around the protective envelope.

Referring now to FIG. 1 of the drawing, there is shown a side view of a.rod or wire 1 made of magnetic material. The element 1 may be generallyof parallel section. As shown in FIG. 2 the element 1 may be flattenedat its opposite ends to form a short portion 2 and a longer portion 4.The outer end of the portion 2 on one side thereof is then electroplatedwith a metal of good electrical conductivity such as platinum, rhodium,silver, etc. A similar plating will be applied to the corresponding sideof the outer end of the portion 4, as indicated at 5. Alternatively,contact surfaces could be welded or riveted to the portions 3 and 5 asis understood by those skilled in the art.

FIG. 3 is a front view of the rod shown in FIG. 2. From FIG. 3 it may beseen how the portion 1a connects the portions 2 and 4, respectively.

As shown in FIG. 4, the bar 1 is given a first U-shaped bend in themiddle of the portion 1a so that the portion 1a has two parallel sides6, 8, which are spaced a distance equal to the diameter of the curvearound which it is bent. The portion 4 is bent near the middle so that aparallel portion 4a extends towards the arm 8 so that the contactportion 5 is adjacent to the contact portion 3. The bend of the portion4 is in the form of a ring shown at 7 and which ring provides aresilient mounting for the arms 4a. The ring 7 will also aid inpreventing fatigue to the bend in the portion 4. The ring 7 may also,under certain conditions, provide a clamping point for centering andsecuring the element when it is positioned within a vessel. The tensionin the arm 4a is such that the contact portion 5 is normally out ofcontact with the corresponding portion 3.

After formation of the structure shown in FIG. 4, the entireorganization is inserted into an envelope 9 which may be of glass or anysuitable material. The envelope 9 may be sealed around the arms 6 and 8at 10. By means of the tubulation 11, the envelope 9 may be evacuatedand, if desired, an inert gas may be introduced Within the envelope toprevent oxidation of the contacts due to arcing when in operation. Thetubulation 11 may be sealed off in accordance with known techniques andwill not be further described. After the sealing of the envelope 9 theconnecting portion 12 of the member 1 may be cut away along the line AAthereby forming two terminals 13, 14 for connection to an externalelectrical circuit (not shown) and which it is desired to control.

By applying a magnetic flux to the middle of the envelope 9 and from itsexterior, the arm 4a may be caused to be drawn downwardly causing thecontact portion 5 to close against the contact portion 3, thuscompleting an electrical circuit. The magnetic flux just mentioned, maybe derived either from a permanent magnet (not shown) or from anelectromagnetic winding 29 which may be disposed thereabout the envelope9 as shown, for instance, in FIG. 9.

The resultant gap between the contact surfaces 3 and 5 may be adjustedbefore enclosing the member 1 within the envelope 9. Such adjustment isnot critical and the ring 7 lends itself to such ready adjustment.

The aipplicaton of magnetic flux to the portions 4, 4a and 2, causes theacceleration of the portion 4a, which now acts as an armature, away fromthe arm 4, and the portion 2 exerts a braking action on the speed of thedisplacement of the movable arm 4a. This acceleration and braking actionis an important effect derived from the unique construction disclosed.

The output terminals 13 and 14 shown in FIG. 5 will be seen to extendfrom one end of the envelope 9 and this enables the mounting of thecompleted switch in a socket similar to the type used for the mountingof electronic tubes. When an electromagnetic coil is placed about theexterior of the tube 9 and is connected to a current source to providemagnetic lines of force along the elements 2, 4 and 4a, it therebycauses displacement of the movable contact 5 towards the stationarycontact 3 to close the circuit between terminals 13 and 14. The flux inthe portions 4 and 4a causes a repulsion therebetwen and which flux actsto dampen the rebound effect when the contacts are open.

It will be understood that the material from which the rod 1 is selectedshould have a coefficient of expansion similar to the glass or othermaterial from which the envelope 9 is made.

This invention is not limited to a single make-contact switching device,as shown in FIGS. l-S, but the invention may also be utilized to providea single pole, double- .throw contact arrangement. This embodiment iscontained in FIGS. 6-9. In FIG. 6 a longitudinal plan view of the rod 1is shown after it has been subjected to a number of forming operations.The rod 1 is flattened at its opposite ends to provide portions 15 and16 respectively, and in addition, there is an intermediate flattenedportion 17, as shown. Thus, the central flattened portion 17 isconnected to the end-flattened portions by means of connecting portions18 and 19, respectively. The portions 18 and 19 have the samecross-section as the original rod 1. The portions 15, 16 and 17 are allin the same plane. The end of the portion 15 is coated with a contactmaterial 20 on one side thereof and the end of the portion 16 is coatedwith contact material 21 on both sides thereof. The portion 17 is coatedat a point nearer to the end 16 with a material 22 having goodelectrical conductivity on one side thereof, such side being identicalwith the side of the coating 20. In lieu thereof, a contact having apredetermined thickness may be secured to the portion 17 by welding orby any other suitable fastening means. The contact 22 is made with apredetermined thickness because it is to be used as a spacing elementfor reasons which will be later explained. After application of thecontacting surfaces, as aforesaid, the member 1 is bent as shown in FIG.7 and which figure is a side view of the structure shown in FIG. 6,after bending thereof. The connecting portion 18 is bent into a U-shapeand the connecting portion 19 is similarly bent into a U-shape. It willnow be seen that the double-coated end 16 lies between the coating 20and contact 22. It will be seen from FIG. 7 that the flattened portions15, 16 and 17 are situated at the center of the organization, whereas,the connecting portions 18 and 19 are at opposite ends thereof. Thethickness of the contact 22 should be suflicient so that the contact 21normally lies thereagainst. This will be the back contact of the switch.The spacing between the fixed contact 20 and the other side of contact21 should be such that there is a gap of predetermined lengththerebetween. The fiat portions 15, 16 and 17 are bent inwardly towardeach other, as shown in FIG. 7, to achieve the desired gap spacing. Theentire organization of FIG. 7 may be then inserted into an envelope 23having ends 24 and 25, respectively, and the connecting portions 18 and19 may be sealed at said ends as shown in FIG. 8. After sealing, twohaiDpin-shaped loops will extend outwardly from opposite ends of theenvelope. These ends may be severed as shown in FIG. 9 thereby definingfour terminals to which connection may be made for control of anexternal electrical circuit (not shown). Thus, the terminal 26 will beconnected to the movable contact 21; the terminals 27, 27a will beconnected to the fixed back contact 22 and the terminal 28 will beconnected to the front contact 20. The winding 29 may surround theenvelope and may be energized over its leads 30 and 31 by connectionthereof to a suitable potential source.

While we have described above the principles of our invention inconnection with specific apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of our invention as set forth in the objects thereof and inthe accompanying claims.

We claim:

1. A magnetically controlled electric switch, comprising a first and asecond metal bar each formed from a single piece of magnetic materialand each having a flattened portion joined by a portion of greaterthickness than the flattened portion, a plurality of electric contactsone at the flattened end of each bar, said first bar being bent backupon itself at a pair of points intermediate its ends to form asubstantially complete single loop and with said flattened portions inclosely spaced magnetic relation throughout their lengths, an enclosingevacuated envelope within which said flattened portions and saidcontacts of each bar are enclosed with the said thick portion of eachbar extending externally out of one end of said envelope and sealedtherethrough in a vacuum-tight manner, and with the ends of the saidflattened portion of said bars overlapped to position the said contactsinto registry with each other.

2. An electric switch as set forth in claim 1 wherein an electromagneticwinding is disposed outside said enevolpe in flux relation with saidflattened [closed] closely spaced portions of said first bar so thatenergization of said winding causes the contact-carrying flattened endof said first bar to be moved as an armature away from the contact onsaid second bar.

3. A magnetically controlled switch according to claim 1 in which one ofthe said bends is enclosed within said envelope and provides a flexiblejoint between said flattened [closed] closely spaced portions of thesaid first bar.

4. A magnetically controlled switch according to claim 1 in which one ofthe said bends is enclosed within said envelope and is formedintermediate the ends of said flattened portion of the said first bar.

5. A magnetically controlled switch according to claim 4 in which saidbend has a diameter of curvature which is greater than the spacingbetween said flattened closely spaced portions of said first bar.

6. The magnetically controlled switch according to claim 1 in which theportion of greater thickness is separated into two sections by a thirdflattened portion having an electrical contact thereon, one of said pairof points being in one of said two sections and the other of said pairof points being in the other of said two sections, the over-lapped endsof said flattened portions being positioned adjacent said thirdflattened portion and oriented to form a single pole, double throwswitching combination.

7. The magnetically controlled switch according to claim 6 wherein oneof said two sections extends externally out of one end of said envelopeand the other of said two sections extends externally out of the otherend of said envelope, said two sections being sealed into the ends insaid vacuum-tight manner.

8. A magnetically controlled electric switch, comprising a first and asecond metal bar formed from a single piece of magnetic material, eachof said bars having a flattened portion joined by at least one portionof greater thickness than the flattened portion, a plurality of electriccontacts one at the flattened end of each bar, said magnetic materialbeing bent back upon itself at a pair of points intermediate its ends toform a substantially complete single loop, an enclosing evacuatedenvelope within which said flattened portions and said contacts of eachbar are enclosed with the said thick portion of each bar extendingexternally out of at least one end of said envelope and sealedtherethrough in a vacuum-tight manner, and with the ends of the saidflattened portion of said bars overlapped to position the said contactsinto registry with each other.

9. A magnetically controlled electric switch comprising a magnetic reedcontact member formed from a single elongated piece of magneticmaterial, said material enclosed in an envelope being flattened at thetwo ends and at a central portion thereof, at least each of said endsand said central portion having a good electrically conductive materialthereon sealed in said envelope, the unflattened parts of said magneticmaterial having two points with a substantially U-shape projectingbeyond said en velope so that the two flattened ends have their facesparallel and overlapping with each other and parallel to a face of theflattened central portion, said U-shaped projections being cm apartoutside said envelope, and said electrically conductive material beingoriented to provide a single throw, double pole contact combination.

10. The electric switch as set forth in claim 9 in which said contactcombination is sealed in an evacuated envelope, and an electromagneticwinding disposed outside said envelope, one of the two ends beingrelatively more movable than the other and responsive to flux generatedwhen said winding is energized, the movable end being normallypositioned to rest on the contact formed by the flattened centralportion of the magnetic material, the other less movable of said twoends being positioned to make electrical contact with said movable endresponsive to flux generated when said winding is energized.

11. A reed switch assembly forming a break-make contact combinationhaving two stationary reed contacts with a movable reed contactpositioned between them, said three reeds being sealed in an envelope,said movable reed contact extending in substantially parallel relationwith one of said stationary reed contacts which said movable contacttouches when in a rest position, said one stationary contact being anelongated piece of magnetic material extending through one end of saidenvelope, across the entire envelope, and out the other end of theenvelope, said movable reed contact extending in a substantially alignedseries relation with the other of said stationary reed contacts withsaid movable contact spaced away from said other stationary contact whenin a rest position, and means external to said envelope for generatingmagnetic flux in said reeds to cause said movable contacts to break fromsaid one stationary reed and to touch said other stationary reed.

References Cited by the Examiner The following references, cited by theExaminer, are of record in the patented file of this patent or theoriginal patent.

UNITED STATES PATENTS 684,094 10/1901 Potter 200144 1,509,965 9/1924MacFarland 2001 13 1,583,496 5/1926 Shafer 200122 1,791,888 2/1931 Dorn20087 1,894,150 1/1933 Beers 200138 2,060,235 11/1936 Miller 2001442,245,391 6/1941 Dickten 20087 2,289,830 7/1942 Ellwood 20087 2,406,0218/1946 Little 20087 2,457,218 12/ 1948 Ferrell 4981 2,506,414 5/ 1950Ellwood 20087 2,611,352 9/1952 Molyneux 20090 2,653,199 9/1953 Brown etal. 20087 2,845,506 7/1958 Delucia 20087 2,892,051 6/ 1959 Moore 20081.92,929,895 3/ 1960 Shebanow 20087 2,969,434 1/1961 McGuire et al. 20087FOREIGN PATENTS 1,028,039 9/ 1950 France.

BERNARD A. GILHEANY, Primary Examiner.

B. DOBECK, Assistant Examiner.

